An apparatus for analyzing a test substance contained in a cell by imaging a cell and processing the captured image is used in facilities such as hospitals. This type of apparatus generally has a configuration for extracting and displaying an image including a test substance from a captured image. When examining the result of analysis by the apparatus, the operator can visually confirm the appearance state of the test substance by appropriately displaying an image including the test substance on a monitor or the like.
Japanese Patent Application Publication No. 07-286952 describes a configuration that cuts out an image of particles such as cells from a captured image to generate a display image. In this configuration, particle images 311 to 314 are displayed in the display areas 301 to 304 as shown in FIG. 24. The areas other than the images 311 to 314 of the particles in the display areas 301 to 304 are filled with white or black, or are painted out with the average density data of the background portions of the particle images 311 to 314.